Modding tuning and best performance upgrades on the Nissan VG20DET engine!

Tuning guide "VG20DET Modifications"

VG20DET Modifications Guide

How to modify and upgrade the Nissan VG20DET

"Comprehensive guide to performance tuning the Nissan VG20DET engine!"

Our friends at TorqueCars often are seeing threads about how to improve the VG20DET from people inquiring about getting more power from the VG20DET and wanting to know what are the greatest VG20DET power upgrades. So let us look into Nissan VG20DET tuning mods and outline the best upgrades on this great engine and point out some problems along the way.

In this article we consider VG20DET tuning and outline the greatest modifications. Nissan VG20DET have loads of potential and with carefully chosen mods like remapping, turbo kits and camshafts you will definitely increase your driving enjoyment.

The ultimate VG20DET modifications on an engine are usually the ones that give the biggest return for your money.

We won't be swayed by popular VG20DET modifications, they need to be cost effective.

VG20DET induction kits

Improving air intake on the VG20DET

You need fuel and air for an engine to work. If there is a lack of fuel then it will run lean, if there is not enough air it runs rich resulting in lost power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Shoving more fuel and air into each cylinder is the main goal to any car tuning project.

You'll commonly see there is a limit in the air flow sensor MAP/MAF/AFM on the VG20DET when considerably more air is being fed into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting torque at a much lower level.

Intake take the air during the suck phase from the air filter and allow it to be fed into the engine cylinders with fuel for the squish phase.

Design and flow rate of the Air Intake manifolds can make a big change to fuel atomisation on the VG20DET.

I usually find intake headers are in dire need of performance upgrades, although some makers provide fairly well optimized intake headers.

Adding a VG20DET larger valve kit, doing a bit of port matching and head flowing will also increase performance, and significantly will afford you increasing the performance increase on other upgrades.

VG20DET performance cam tips.

Some VG20DET engines respond better to different camshaft durations so set your engine up on a rolling road.

The ecu map and fuelling also will say much on the bhp gains you'll hit.

Altering valve durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

Altering your VG20DET cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road cams commonly raise the torque through the rpm range, you may sacrifice a little low end torque but your high end rpm power will be lifted.

Motorsport cams, raise the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a road car you should ideally to optimize your power band to your usage of the car.

You will never have ever thought a VG20DET Motorsport and race camshaft is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the VG20DET

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 VG20DET parts:

Intake headers, Remaps/piggy back ECU, Fast road camshaft, Sports exhaust manifold, Panel air filters, Drilled & smoothed airbox.

Stage 2 VG20DET parts:

Sports catalyst & performance exhaust, Fast road cam, fuel pump upgrades, high flow fuel injectors, induction kit, Ported and polished head.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 3 VG20DET parts:

Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Engine balancing & blueprinting, Twin charging conversions, Competition cam.

The VG20DET engines are fantastic to work on and we're finding that there are increasing numbers of modifications and tuning parts about.

Remaps helps unlock the full potential of all the tuning mods you've done to your VG20DET.

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your results usually vary depending on the tuning mods you've carried out and the condition of your engine.

Turbo modifications on the VG20DET

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the VG20DET.

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes superb power gains.

If an engine has forced induction tuning mods are going to net you a larger power gain and you will discover turbo charged engines will have more solid components.

There are tuning limits for every engine, with some being extremely strong and some only just able to handle stock power

It is important to find these restrictions and install forged components to survive the power.

It's not unheard of drivers spending a loads on turbocharger upgrades on the VG20DET only to suffer the humiliation of seeing the engine block throw a rod on it's first outing after it's been enthusiastically driven.

Big turbo units commonly experience low end lag, and little turbo units spool up much more quickly but don't have the high rpm power band gains.

We are pleased that the world of turbos is always moving on and we now see variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbos divert the exhaust flow into two channels and flow these at differently profiled vanes in the turbo. They also boost the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large power gains, although more challenging to configure. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the VG20DET

You will need to ensure that the engine is not starved of fuel so will have to look at the fuelling when you start going beyond 20% of a performance hike. We strongly recommend you to over specify your injectors flow rate.

The rule of thumb is to add 20% when fitting an injector, this takes into account injector deterioration and allows some spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended VG20DET performance exhaust upgrades

The only time you should look to improve your exhaust system with an upgraded one is if your current exhaust is creating a flow problem.

On most factory exhausts you'll see the exhaust flow rate is ok even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts can usually air flow out of the engine but do not go too large or you could will reduce the flow rate. Stick to one and a half to two and half inches for best results.

Typically exhaust restrictions are traced to the catalysts installed, so adding a faster flowing high performance alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the VG20DET

Like most engines an VG20DET, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the VG20DET, failure to do this will exacerbate engine wear, on a tuned VG20DET this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your VG20DET why not pop over to the forums at TorqueCars where you can chat about VG20DET tuning options and read about others projects who may be planning to do similar modifications on their VG20DET.

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